<%@page import="java.util.ArrayList"%>
<%@page import="java.util.List"%>
<%@page import="entity.User"%>
<%@ page contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<html>
	<head>
	<title>Insert title here</title>
	</head>
	<body>
		${100+100}<br>
		${1<2}<br>
		${"1"+"4" }<br><!--不会拼接字符串,会转换为数字,若转换数字失败,则报错!-->
		<%-- ${"a"+"b" }--%><!--el表达式不能做字符串拼接,尝试转换为数字失败-->
		<%
			User1	User uUser=User1 User();
				user.setUsername("zhangsan");
				request.setAttribute("user", user);
				request.setAttribute("s2", "");
				request.setAttribute("s3", " ");
				List list1 = new ArrayList();
				request.setAttribute("list1", list1);
		%>
		${user.username=='zhangsan' }<br>
		${1<2 && 3>5}<br>
		${user.username=='zhangsan' || 1<1 }<br>
		空字符串:${empty s2 }<br><!--''和null empty都返回true-->
		空格字符串:${empty s3 }<br>
		找不到字符串:${empty ss }<br>
		空集合:${empty list1 }<br><!--集合里没元素为空-->
		找不到对应的集合:${empty listt }<br><!--找不到集合为空-->
		null:${empty null }<br><!--true-->
		
		name: ${param.name } <br><!--从网址上传参数 /e3.jsp?name=ls&hobbies=111&hobbies=222-->
		hobbies:${paramValues.hobbies[1] }<br><!--从网址上传参数,不传得到空而不是返回null-->
	</body>
</html>